ETonline traveled to Vancouver, to check out the set that houses the fastest man alive and toured the hallowed halls of Central City's finest establishments. Not only did we get some serious scoop from the stars — more coming soon — we were delighted to discover a DC Comics Easter egg that viewers at home have not had the chance to enjoy, or — let's be honest — completely lose their minds over!

In the lobby of Central City's 1940's-inspired police department, The Flash's head production designer Tyler Harron was determined to gift fans with an entire wall's worth of secret superhero fun.

"When I found out that I was going to do this show, this was the first thing that I designed," Harron spilled to ETonline on the set of The Flash. "I've always been a huge DC fan and so it was really easy for me to say that I need to put this one Easter egg in here. All of the sets were based off of this."

To the untrained eye, the sweeping mural that stands as the hearth of Central City P.D. simply looks like the Greek Gods of Mt. Olympus—with Hephaestus, Hermes, Hera, Zeus, Hades, Apollo, and Poseidon reigning over the room from left to right.

But to those who know and love the DC Comic lore, these mythological gods are actually the Justice League in disguise! Looking a little closer, you can see we've got Superman as Zeus (Jupiter), Batman as Hades (Pluto), Wonder Woman as Hera (Juno), the Flash as Hermes (Mercury), Green Arrow as Apollo, Aquaman as Poseidon (Neptune), and the Green Lantern as Hephaestus (Vulcan). Pretty amazing, right?

To further your ah-hah! moment, Harron also inscribed three words to the bottom of the mural: Truth, Liberty, and the biggest word of all: Justice.

"I wanted to do a deco [themed] set and [the sculpting style of] bas-relief in the deco era was rampant and so was the Greek mythology in their sculptures," Harron explained. "So I said I'd like to put in an Easter egg that represents all each one of the Justice League members." Harron told us that it took approximately three weeks and three sculptors to complete the grandiose wall.

Harron's breathtaking page-to-set transformation has quickly become a favorite with all of the actors of The Flash — especially the fastest man alive himself. "The lobby of the police station is pretty amazing," Grant Gustin said.

And like his character, Gustin was speedy to unveil the Justice League secret when Harron initially presented him with the on-set Easter egg. "I first took Grant in here when we were building the set, but some of the walls hadn't been finished," Harron said. But Gustin had a hunch. "He said, 'Oh there's something in there — I know it!'"

"So I took a photo and I sent it down to him," Harron explained. "And I said, 'I'm not telling you what it is, you'll have to figure it out.' He came back right away and he had it all written down. He had it all figured out."

Harron's devotion to the Justice League has become his "favorite piece" of his career, and despite all of the hours and attention to detail the designer poured into the mural's completion, Harron's request for a reward is a simple one: "I'm just waiting for a nice photo of The Flash in front of it."

See the disguised Justice League mural for yourself when The Flash airs Tuesdays at 8 p.m. on The CW.